Sex differences in polysomnographic findings in patients with obstructive sleep apnea

BACKGROUND AND PURPOSE

Sex differences in the clinical findings and the polysomnographic presentation of patients with obstructive sleep apnea (OSA) are compelling current research issues. For example, patients suffering from obstructive sleep apnea are predominantly male. While women are older than men and tend to have a higher body mass index, men typically present with a more severe form of obstructive sleep apnea. Using polysomnography, we investigated a German cohort, subdivided per severity levels of obstructive sleep apnea (apnea-hypopnea index: ≥5 to < 15/h (mild), ≥15 to < 30/h (moderate), and ≥30/h (severe)) to provide a detailed analysis of breathing and sleep parameters, accounting for body position effects and severity of illness. A deeper understanding of sex differences may allow targeted diagnosis and treatment adjustment.

PATIENTS AND METHODS

This retrospective study included a cohort of 1242 German patients (940 male, 302 female) who underwent overnight polysomnography at the private sleep laboratory "Intersom Köln", Center for Sleep Medicine and Sleep Research. In 1125 subjects (878 male, 247 female), obstructive sleep apnea was diagnosed. All patients were examined between January 01, 2018 and December 31, 2020, comparing anthropometric, sleep morphological, and respiratory polysomnographic findings.

RESULTS

Female patients with obstructive sleep apnea were significantly older than male patients (60.9 ± 12.3 vs. 56.9 ± 12.5 years, P < .001), also among OSA subgroups per OSA severity. The body mass index was similar in male and female patients (29.6 ± 5.1 vs. 29.2 ± 7.3 kg/m², P > .05), including the three subgroups. Men were more likely to have severe obstructive sleep apnea (46.9%) than women (35.2%). Women exhibited a higher proportion of slow-wave sleep than men (129.4 ± 52.8 vs. 104.2 ± 53.2 min; P < .001). The apnea-hypopnea index of total sleep time was significantly greater in male than female patients (32.9 ± 21.2 vs. 27.2 ± 20.2 per hour; P < .001). Female patients had a higher apnea-hypopnea index during rapid-eye-movement (REM) sleep (34.0 ± 23.8 vs. 31.8 ± 22.3 per hour; P = .171). A statistically significant difference in the apnea-hypopnea index during REM sleep between sexes was found when the obstructive sleep apnea severity was considered. Women had a lower apnea-hypopnea index in non-rapid eye-movement (NREM) sleep than men (25.7 ± 21.1 vs. 32.7 ± 22.3 per hour; P < .001). The oxygen desaturation index (29.9 ± 20.3 vs. 22.4 ± 19.4%; P < .001) and an oxygen desaturation below 90% (9.4 ± 14.0 vs. 6.8 ± 11.7%; P = .003) was greater in men than in women. In severe obstructive sleep apnea, the oxygen desaturation index was similar between the sexes (45.0 ± 17.8 vs. 41.1 ± 20.9%; P = .077). Male patients showed a higher supine apnea-hypopnea-index than female patients. (45.7 ± 26.7 vs 36.1 ± 22.7 per hour; P < .001).

CONCLUSION

The present noninvasive, retrospective registry study is the first to examine sex differences in OSA in such a large German population in terms of respiratory and sleep parameters, taking into account the effects of body position and severity of the disease. We could confirm and extend observations from previous studies. Female patients were significantly older than the male patients. The apnea-hypopnea index was higher in male than in female patients. Women showed a higher apnea-hypopnea index in REM sleep and a lower one in NREM sleep. Men were desaturated more often and were more affected by supine-dependent obstructive sleep apnea than women. Contrary to the literature, there were no significant differences in body mass index (BMI) between the sexes. With increasing age and BMI, the gender differences become less significant.

Associations between sleep, obesity, and asthma in urban minority children

STUDY OBJECTIVES

Although obesity, asthma, and sleep-disordered breathing are interrelated, there is limited understanding of the independent contributions of body-mass index and pulmonary function on polysomnography in children with asthma.

METHODS

We conducted a retrospective chart review on 448 7- to 18-year-old children with asthma who had undergone polysomnography testing between 1/2007-12/2011 to elucidate the association between spirometry variables, body-mass index, and polysomnography parameters, adjusting for asthma and antiallergic medications.

RESULTS

Obese children had poorer sleep architecture and more severe gas exchange abnormalities compared to healthy weight children. Multivariate analysis revealed an independent association of body-mass index with sleep efficiency, with more light and less deep sleep in both obese and healthy-weight children, and with baseline oxygen saturation and oxygen nadir in obese children. In obese children, forced vital capacity was independently associated with less deep sleep (time in N3 sleep) as well as with oxygen nadir, while among healthy-weight children, forced expiratory volume directly correlated but forced vital capacity inversely correlated with deep sleep. In obese children, inhaled corticosteroid was associated with baseline oxygen saturation, and montelukast was associated with lower end-tidal carbon dioxide. In healthy-weight children, inhaled corticosteroid was associated with arousal awakening index, and montelukast was associated with light sleep. Antiallergic medications were not independently associated with polysomnography parameters.

CONCLUSIONS

Pulmonary function, body-mass index, and asthma medications have independent and differing influences on sleep architecture and gas exchange polysomnography parameters in obese and healthy-weight children with asthma. Asthma medications are associated with improved gas exchange in obese children and improved sleep architecture in healthy-weight children with asthma.

CITATION

Conrad LA, Nandalike K, Rani S, Rastogi D. Associations between sleep, obesity, and asthma in urban minority children. J Clin Sleep Med. 2022;18(10):2377-2385.

The 3% Oxygen Desaturation Index is an Independent Risk Factor for Hypertension Among Children with Obstructive Sleep Apnea

BACKGROUND

Obstructive sleep apnea (OSA) and obesity are both directional risk factors of hypertension. Chronic intermittent hypoxemia (IH) is a commonly observed pathophysiological mechanism involved in multiple comorbidities of OSA. However, their interactions are not well understood in children. This study aimed to investigate the associations of IH indexes (oxygen desaturation index 3% [ODI3], mean peripheral oxygen saturation [SpO₂], least SpO₂, and time with SpO₂ < 85%), apnea-hypopnea index, and weight status with hypertension in a sample of pediatric OSA patients.

METHODS

The medical records of 365 pediatric OSA patients were retrospectively reviewed in this cross-sectional study. Demographics, anthropometrics, standard in-laboratory polysomnography, and nocturnal blood pressure were collected. Multivariate logistic regression with forward selection was used to identify independent predictors of hypertension.

RESULTS

Multivariate logistic regression analysis showed that ODI3 (odds ratio [OR] = 1.02, 95% confidence interval [CI] = 1.01-1.03) and body mass index z-score (OR = 1.34, 95% CI = 1.12-1.60) were independent continuous predictors of pediatric hypertension, whilst severe OSA (OR = 2.62, 95% CI = 1.60-4.29) and overweight/obesity (OR = 2.63, 95% CI = 1.59-4.34) were independent categorical predictors. Traditional risk factors including male sex (OR = 2.33, 95% CI = 1.02-5.33), late childhood/adolescence (OR = 1.98, 95% CI = 1.01-3.88), and overweight/obesity (OR = 2.97, 95% CI = 1.56-5.67) combined with sleep hypoxemia (least SpO₂ ≤ 95%) (OR = 2.24, 95% CI = 1.16-4.04) predicted hypertension (R ² = 0.21) in the severe IH subgroup (n = 205), while the no/mild IH subgroup (n = 160) had an entirely different predictor, severe OSA (OR = 3.81, 95% CI = 1.49-9.74) (R ² = 0.07).

CONCLUSION

The close relationships among IH, overweight/obesity, and hypertension highlight the importance of reducing IH and body weight in children with OSA.

Overnight variation in tidal expiratory flow limitation in COPD patients and its correction: an observational study

Background

Tidal expiratory flow limitation (EFL_T) is common among COPD patients. Whether EFL_T changes during sleep and can be abolished during home ventilation is not known.

Methods

COPD patients considered for noninvasive ventilation used a ventilator which measured within-breath reactance change at 5 Hz (∆Xrs) and adjusted EPAP settings to abolish EFL_T. Participants flow limited (∆Xrs > 2.8) when supine underwent polysomnography (PSG) and were offered home ventilation for 2 weeks. The EPAP pressure that abolished EFL_T was measured and compared to that during supine wakefulness. Ventilator adherence and subjective patient perceptions were obtained after home use.

Results

Of 26 patients with supine EFL_T, 15 completed overnight PSG and 10 the home study. In single night and 2-week home studies, EFL_T within and between participants was highly variable. This was unrelated to sleep stage or body position with only 14.6% of sleep time spent within 1 cmH₂O of the awake screening pressure. Over 2 weeks, mean EPAP was almost half the mean maximum EPAP (11.7 vs 6.4 cmH₂O respectively). Group mean ∆Xrs was ≤ 2.8 for 77.3% of their home use with a mean time to abolish new EFL_T of 5.91 min. Adherence to the ventilator varied between 71 and 100% in prior NIV users and 36–100% for naïve users with most users rating therapy as comfortable.

Conclusions

Tidal expiratory flow limitation varies significant during sleep in COPD patients. This can be controlled by auto-titrating the amount of EPAP delivered. This approach appears to be practical and well tolerated by patients.

Trial registration: The trial was retrospectively registered at CT.gov NCT04725500.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01913-7.

[The impact of unilateral diaphragmatic paralysis on sleep-disordered breathing: a scoping review]

BACKGROUND

Unilateral diaphragm paralysis (UDP) may potentially worsen sleep-disordered breathing (SDB). Unilateral diaphragm paralysis has been associated with proximal brachial plexus blockade, such as interscalene and supraclavicular block. The impact of UDP in patients with SDB is not known in this context. The objectives of this scoping review were to explore the associations between UDP and worsening SDB severity, oxygenation, and pulmonary function.

METHODS

A systematic search was developed, peer-reviewed, and applied to Embase, Medline, CINAHL, and Cochrane databases to include studies involving adult patients (≥ 18 yr) with SDB, where the effects of UDP on SDB severity, oxygenation, and pulmonary function were examined.

RESULTS

Six studies (n = 100 patients) with UDP and SDB were included. The sample population was derived exclusively from respirology-sleep clinics, and none were surgical patients. Compared with control (no UDP), UDP was associated with an increased respiratory disturbance index, most pronounced during rapid eye movement (REM) sleep and supine sleep. Supine and REM sleep were associated with obstructive and mixed (both obstructive and central) events, respectively. Compared with control, UDP was associated with a lower mean and minimum oxygen saturation and arterial oxygen tension during all sleep stages and in all body positions. The majority of UDP patients were found to have clinically significant reductions in mean forced expiratory volume in one second and forced vital capacity values, consistent with restrictive ventilatory pattern.

CONCLUSION

We observed an association between UDP and increasing SDB severity, particularly during REM sleep and while sleeping in the supine position. Although we identified weaknesses in study design and lack of perioperative data, anesthesiologists should be aware of this association when considering proximal brachial plexus blockade in patients with SDB.

Small airways' function in Obstructive Sleep Apnea-Hypopnea Syndrome

INTRODUCTION AND OBJECTIVES

Most of the studies of the pathophysiology of Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS) focus on the collapsibility and obstruction of the upper airways. The aim of our study was the investigation of small airways' function in patients with OSAHS.

MATERIALS AND METHODS

We studied 23 patients (mean age, 51.6 years) diagnosed with mild to severe OSAHS, without comorbidities and 8 controls (mean age, 45.9 years). All subjects underwent full polysomnography sleep study; spirometry and maximum flow/volume curves while breathing room air and a mixture of 80%He-20%O₂. The volume of equal flows (VisoV⋅) of the two curves and the difference of flows at 50% of FVC (ΔV˙max₅₀) were calculated, as indicates of small airways' function.

RESULTS

The results showed that VisoV⋅ was significantly increased in patients with OSAHS compared with controls (18.79±9.39 vs. 4.72±4.68, p=0.004). No statistically significantly difference was found in ΔV˙_max50% (p=0.551); or the maximum Expiratory flow at 25-75% of FVC (p=0.067) and the maximum expiratory flow at 50% of FVC (p=0.174) breathing air.

CONCLUSIONS

We conclude that at the time of the diagnosis of OSAHS, the function of the small airways is affected. This could be due to breathing at low lung volumes and the cyclic closure/opening of the small airways and may affect the natural history of OSAHS. The findings could lead to new therapeutic implications, targeting directly the small airways.